Japanese Unexamined Patent Application Publication No. 2015-228371 discloses an illumination light source device that includes a light source unit including a primary light source that emits primary light, a plurality of light conversion units including light conversion elements that convert optical properties of the primary light to generate secondary light, and a connecting portion that detachably connects the light conversion unit in a light guide path. Japanese Unexamined Patent Application Publication No. 2015-228371 discloses that a semiconductor laser is used as the primary light source, and a fluorescent material is used as the light conversion unit.